We can handle varying window labels using regular expression Win Runner uses two “hidden” properties in order to use regular expression in an object physical descriptions, these properties are regexp_label abd regexp_MSW class .

The regexp_label property is used  for windows only . it operates  behind the secene  to insert a regular expression into a windows label  descriptions

The regexp_MSW_class property insert a regular expression into an object’s  MSW_class . it obligatory for all types of window and for the object class object